The present disclosure is directed at skeletal bone fixation systems, components thereof, and methods of implant placement. These devices are used during the surgical reconstruction of skeletal segments to bridge bony gaps and to adjust, align and fixate the remaining bone or bony fragments
Whether for degenerative disease, traumatic disruption, infection or neoplastic invasion, the surgical resection of bone and the subsequent reconstruction of the skeletal segment is a common procedure in current medical practice. Regardless of the anatomical region or the specifics of the individual operation, many surgeons employ an implantable device to bridge the region of bone resection and provide structural support for the remaining skeletal segment. These devices are especially useful in spinal surgery where they are used to restore spinal alignment and to stabilize the spinal column after vertebral and/or disc resection.
While these devices provide immediate structural support of the operative segment, long term stability requires that a bone graft be used to replace the resected bone and that the grafted bone successfully incorporate (“fuse”) within the skeletal segment. For these reason, many devices are designed with a rigid outer structure that is intended to provide immediate stability and a hollow central cavity that is used to retain the bone graft while the bony fusion proceeds.
Unfortunately, this design has a central flaw. In providing stability, the rigid outer structure bears the load transmitted through that skeletal segment and effectively shields the bone graft from stress forces. Since bone fusion occurs most effectively when the healing bone is subjected to load, placement of the graft within the device effectively shields it from stress forces and leads to a significant reduction in the likelihood of bony fusion. In addition, stress shielding will also significantly diminish the quality and density of the fusion mass that will eventually develop.